docs: def set_itunes_keywords(self):
          """Parses itunes keywords and set value"""
          try:
              keywords = self.soup.find('itunes:keywords').string
          except AttributeError:
              keywords = None
          try:
              self.itunes_keywords = [keyword.strip()
                                      for keyword in keywords.split(',')]
              self.itunes_keywords = list(set(self.itunes_keywords))
          except AttributeError:
              self.itunes_keywords = []